From patchwork Mon Apr 26 18:42:00 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Gabriel Krisman Bertazi X-Patchwork-Id: 12224869 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,UNPARSEABLE_RELAY,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 78D46C433B4 for ; Mon, 26 Apr 2021 18:45:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4044F61157 for ; Mon, 26 Apr 2021 18:45:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238590AbhDZSpr (ORCPT ); Mon, 26 Apr 2021 14:45:47 -0400 Received: from bhuna.collabora.co.uk ([46.235.227.227]:47610 "EHLO bhuna.collabora.co.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239508AbhDZSn7 (ORCPT ); Mon, 26 Apr 2021 14:43:59 -0400 Received: from [127.0.0.1] (localhost [127.0.0.1]) (Authenticated sender: krisman) with ESMTPSA id A0D821F422D6 From: Gabriel Krisman Bertazi To: amir73il@gmail.com, tytso@mit.edu, djwong@kernel.org Cc: david@fromorbit.com, jack@suse.com, dhowells@redhat.com, khazhy@google.com, linux-fsdevel@vger.kernel.org, linux-ext4@vger.kernel.org, Gabriel Krisman Bertazi , kernel@collabora.com Subject: [PATCH RFC 14/15] samples: Add fs error monitoring example Date: Mon, 26 Apr 2021 14:42:00 -0400 Message-Id: <20210426184201.4177978-15-krisman@collabora.com> X-Mailer: git-send-email 2.31.0 In-Reply-To: <20210426184201.4177978-1-krisman@collabora.com> References: <20210426184201.4177978-1-krisman@collabora.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org Introduce an example of a FAN_ERROR fanotify user to track filesystem errors. Signed-off-by: Gabriel Krisman Bertazi --- samples/Kconfig | 7 ++ samples/Makefile | 1 + samples/fanotify/Makefile | 3 + samples/fanotify/fs-monitor.c | 135 ++++++++++++++++++++++++++++++++++ 4 files changed, 146 insertions(+) create mode 100644 samples/fanotify/Makefile create mode 100644 samples/fanotify/fs-monitor.c diff --git a/samples/Kconfig b/samples/Kconfig index e76cdfc50e25..a2968338517f 100644 --- a/samples/Kconfig +++ b/samples/Kconfig @@ -120,6 +120,13 @@ config SAMPLE_CONNECTOR with it. See also Documentation/driver-api/connector.rst +config SAMPLE_FANOTIFY_ERROR + bool "Build fanotify error monitoring sample" + depends on FANOTIFY + help + When enabled, this builds an example code that uses the FAN_ERROR + fanotify mechanism to monitor filesystem errors. + config SAMPLE_HIDRAW bool "hidraw sample" depends on CC_CAN_LINK && HEADERS_INSTALL diff --git a/samples/Makefile b/samples/Makefile index c3392a595e4b..93e2d64bc9a7 100644 --- a/samples/Makefile +++ b/samples/Makefile @@ -5,6 +5,7 @@ subdir-$(CONFIG_SAMPLE_AUXDISPLAY) += auxdisplay subdir-$(CONFIG_SAMPLE_ANDROID_BINDERFS) += binderfs obj-$(CONFIG_SAMPLE_CONFIGFS) += configfs/ obj-$(CONFIG_SAMPLE_CONNECTOR) += connector/ +obj-$(CONFIG_SAMPLE_FANOTIFY_ERROR) += fanotify/ subdir-$(CONFIG_SAMPLE_HIDRAW) += hidraw obj-$(CONFIG_SAMPLE_HW_BREAKPOINT) += hw_breakpoint/ obj-$(CONFIG_SAMPLE_KDB) += kdb/ diff --git a/samples/fanotify/Makefile b/samples/fanotify/Makefile new file mode 100644 index 000000000000..b3d5cc826e6f --- /dev/null +++ b/samples/fanotify/Makefile @@ -0,0 +1,3 @@ +userprogs-always-y += fs-monitor + +userccflags += -I usr/include diff --git a/samples/fanotify/fs-monitor.c b/samples/fanotify/fs-monitor.c new file mode 100644 index 000000000000..cdece8344c20 --- /dev/null +++ b/samples/fanotify/fs-monitor.c @@ -0,0 +1,135 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright 2021, Collabora Ltd. + */ + +#define _GNU_SOURCE +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#ifndef FAN_ERROR + +#define FAN_ERROR 0x00100000 +#define FAN_PREALLOC_QUEUE 0x00000080 + +#define FAN_EVENT_INFO_TYPE_LOCATION 4 +#define FAN_EVENT_INFO_TYPE_ERROR 5 +#define FAN_EVENT_INFO_TYPE_FSDATA 6 + +struct fanotify_event_info_error { + struct fanotify_event_info_header hdr; + int version; + int error; + long long unsigned fsid; +}; + +struct fanotify_event_info_location { + struct fanotify_event_info_header hdr; + int line; + char function[0]; +}; + +struct fanotify_event_info_fsdata { + struct fanotify_event_info_header hdr; + char data[0]; +}; + +struct ext4_error_inode_report { + unsigned long long inode; + unsigned long long block; + char desc[40]; +}; +#endif + +static void handle_notifications(char *buffer, int len) +{ + struct fanotify_event_metadata *metadata; + struct fanotify_event_info_header *hdr = 0; + char *off, *next; + + for (metadata = (struct fanotify_event_metadata *) buffer; + FAN_EVENT_OK(metadata, len); metadata = FAN_EVENT_NEXT(metadata, len)) { + next = (char*)metadata + metadata->event_len; + if (!(metadata->mask == FAN_ERROR)) { + printf("unexpected FAN MARK: %llx\n", metadata->mask); + continue; + } + if (metadata->fd != FAN_NOFD) { + printf("bizar fd != FAN_NOFD\n"); + continue;; + } + + printf("FAN_ERROR found len=%d\n", metadata->event_len); + + for (off = (char*)(metadata+1); off < next; off = off + hdr->len) { + hdr = (struct fanotify_event_info_header*)(off); + + if (hdr->info_type == FAN_EVENT_INFO_TYPE_ERROR) { + struct fanotify_event_info_error *error = + (struct fanotify_event_info_error*) hdr; + + printf(" Generic Error Record: len=%d\n", hdr->len); + printf(" version: %d\n", error->version); + printf(" error: %d\n", error->error); + printf(" fsid: %llx\n", error->fsid); + + } else if(hdr->info_type == FAN_EVENT_INFO_TYPE_LOCATION) { + struct fanotify_event_info_location *loc = + (struct fanotify_event_info_location*) hdr; + + printf(" Location Record Size = %d\n", loc->hdr.len); + printf(" loc=%s:%d\n", loc->function, loc->line); + + } else if(hdr->info_type == FAN_EVENT_INFO_TYPE_FSDATA) { + struct fanotify_event_info_fsdata *data = + (struct fanotify_event_info_fsdata *)hdr; + struct ext4_error_inode_report *fsdata = + (struct ext4_error_inode_report*) ((char*)data->data); + + printf(" Fsdata Record: len=%d\n", hdr->len); + printf(" inode=%llu\n", fsdata->inode); + if (fsdata->block != -1L) + printf(" block=%llu\n", fsdata->block); + printf(" desc=%s\n", fsdata->desc); + } + } + } +} + +int main(int argc, char **argv) +{ + int fd; + char buffer[BUFSIZ]; + + if (argc < 2) { + printf("Missing path argument\n"); + return 1; + } + + fd = fanotify_init(FAN_CLASS_NOTIF|FAN_PREALLOC_QUEUE, O_RDONLY); + if (fd < 0) + errx(1, "fanotify_init"); + + if (fanotify_mark(fd, FAN_MARK_ADD|FAN_MARK_FILESYSTEM, + FAN_ERROR, AT_FDCWD, argv[1])) { + errx(1, "fanotify_mark"); + } + + while (1) { + int n = read(fd, buffer, BUFSIZ); + if (n < 0) + errx(1, "read"); + + handle_notifications(buffer, n); + } + + return 0; +}